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Patients Treated

Children and adults


Board Certifications

  • American Board of Internal Medicine, 2004, recertified 2014
  • American Board of Allergy/Immunology, 2006, recertified 2015


  • Undergraduate: Fairfield University
  • Medical School: NY College of Osteopathic Medicine
  • Residency: NYU Langone Hospital – Long Island
  • Fellowship: University of Alabama at Birmingham


In college, Dr. Johnston was drawn to immunology and considered a career as an immunologist. After spending time working in the lab, he realized that it would be much more exciting to treat people with allergic and immune disorders, especially since he grew up having both allergic rhinitis and asthma. Dr. Johnston was attracted to Osteopathic medicine because its core principles focus on the body’s ability to function as a whole and heal itself, a key role of the immune system.

Dr. Johnston is a fellow of the American College of Allergy, Asthma, and Immunology and the American Academy of Allergy, Asthma, and Immunology (AAAAI). He has served as chair of the Urticaria/Angioedema subcommittee and the Allergic Skin Disease committee for the AAAAI. He is an Assistant Professor of Medicine at the Edward Via School of Osteopathic Medicine in Spartanburg, SC. and is the featured allergist on the Allergy and Asthma Foundation of America’s “Ask the Allergist” website.

He is very passionate about food allergy, which stems from having a daughter with peanut allergy. He was very excited to participate as a principal investigator and author of the Palisades peanut desensitization study, which led to the FDA approval of a treatment to desensitize children with peanut allergy. In addition, Dr. Johnston has expertise in angioedema and eosinophilic esophagitis (EoE) and has served as principal investigator for novel and future therapies for these disorders. He has lectured at national and international medical conferences and has publications in several medical journals including Clinical Immunology, WAO Journal, Journal of Allergy, Asthma, and Immunology, JAMA, and the New England Journal of Medicine. 

Dr. Johnston continually learns from his patients and is a strong advocate of shared decision-making in medicine. When not working, he enjoys watching soccer, traveling with his wife and two daughters, and making Neapolitan pizza.

Dr. Johnston’s Articles and Publications

 Banerji A, Anderson J, Johnston DT. Optimal management of hereditary angioedema: shared decision-makingJournal of Asthma and Allergy In Press 2021

Johnston DT, Li HH, Craig TJ et al. Androgen use in hereditary angioedema: A critical appraisal and approaches to transitioning from androgens to other therapies. Allergy Asthma Proc 2021;42:1-8

Zuraw B, Lumry WR, Johnston DT et al. Oral once-daily berotralstat for the prevention of hereditary angioedema attacks: a randomized, double-blind, placebo-controlled phase 3 trial. J Allergy Clin Immunol.  Published online OCT 23, 2020

Johnston DT, Smith RC. Hereditary Angioedema: Special considerations in childrenAllergy Asthma Proc 2020;41:S43-46

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